OPTICAL-SPECTRA OF CADMIUM HALIDE CRYSTALS IN 3-30 EV REGION

Reflection spectra of single crystals of CdCl2, CdBr2 and CdI2 at 35 K were measured in the region up to 30 eV using synchrotron radiation. Photoemission experiments were also performed on insitu evaporated films of cadmium halides to determine binding energies of the outermost s-core levels of halogen ions. Optical constants were derived through Kramers-Kronig analysis. In the region up to 15 eV were found a number of peaks which are attributed to the transitions from the halogen valence band to the cadmium 5s and 5p conduction bands. Around 16 eV were observed the peaks due to the Cd Ad core excitons. Weak structures in the 19-24 eV region are assigned to the transitions from the halogen s-core levels. In CdI2, it was found that the total oscillator strength for the transition from the valence band is enhanced due to the presence of shallow core levels. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.